Avalanche Forecast
Regions: Pine Pass.
There is a lot of uncertainty with the reactivity of deeply buried weak layers. Conditions like this are best managed by sticking to lower-angle terrain away from any overhead hazard.
Read more in our latest forecaster blog.
Confidence
Moderate
Avalanche Summary
Reactive wind slabs were reported earlier in the week including explosives triggering up to size 2.5 avalanches on east and southeast alpine features on Tuesday.
Reactive wind slabs will continue to form, but concern for step-down and large natural and human-triggered deep persistent slab avalanches is at the forefront of our minds. Check out this video on incremental loading to learn more.
Please continue to send in your observations through the MIN.
Snowpack Summary
Warm temperatures have produced a crust up to 1600 m, at higher elevations northwest winds formed slabs in lee terrain.
Snowpack depths are shallower than normal, and several buried weak layers have been a concern over the past few weeks. Surface hoar or crust layers in the mid-snowpack may exist in this region, but field observations suggest these mid-snowpack weaknesses are less prominent here than in areas further south.
The most concerning layer in this area is at the base of the snowpack. Large, weak facets buried in November are widespread. This layer is most likely to be problematic in steep, rocky alpine terrain, where shallower wind slab avalanches can scrub down to these basal facets.
Weather Summary
Thursday night
Cloudy with isolated flurries, trace to 5 cm. Ridge wind northwest 20-30 km/hr. Alpine low temperature -8 C. Freezing level dropping to valley bottom.
Friday
Mainly cloudy with isolated flurries, trace accumulation. Ridge wind northeast 20-40 km/hr. Alpine temperature -10 C. Freezing level valley bottom.
SaturdayClearing and mostly sunny. Ridge wind northeast 35-45 km/hr. Alpine temperature -15 C.
SundaySunny. Ridge wind northeast 20-40 km/hr. Alpine temperature -15 C.
More details can be found in the Mountain Weather Forecast.
Terrain and Travel Advice
- Watch for newly formed and reactive wind slabs as you transition into wind affected terrain.
- If triggered, wind slabs avalanches may step down to deeper layers resulting in larger avalanches.
- Avoid thin areas like rock outcroppings where you're most likely to trigger avalanches failing on deep weak layers.
- Uncertainty is best managed through conservative terrain choices at this time.
Avalanche Problems
Wind Slabs
Recent northwesterly winds have redistributed recent snow and pressed surfaces. Expected continued transport and new slabs where wind impacts loose snow.
Aspects: North, North East, East, South East, South, South West.
Elevations: Alpine, Treeline.
Likelihood: Possible - Likely
Expected Size: 1.5 - 2.5
Deep Persistent Slabs
A layer of large and weak facets sits near the base of the snowpack. This layer has most recently been problematic in upper treeline/lower alpine elevations. Riders are most likely to trigger an avalanche on this layer in steep, shallow previously undisturbed terrain, or by first triggering a layer further up in the snowpack.
Aspects: All aspects.
Elevations: All elevations.
Likelihood: Possible
Expected Size: 2 - 3.5